Timer for controlling the operation of devices and implements, especially stoves

ABSTRACT

A timing mechanism especially for cooking appliances, in which a pointer is adjustable over a clock face to indicate the end of a cooking period, while a dial is adjustable to indicate the duration of the cooking period. A planetary gear arrangement interconnects the dial and the pointer and adjusts one of a pair of clutch elements, the other of which is driven by the timer motor. Adjustment of the dial presets a power control device and when the clutch parts are in a certain relative position they clutch together and initiate the supply of power to the appliance, and which is automatically terminated when the preselected time expires.

United States Patent Inventor Josef Neubauer Wendelstein, Germany Appl.No. 874,469

Filed Nov. 6, 1969 Patented Oct. 5, 1971 Assignee o Diehl Nurnberg,Germany Nov. 7, 1968 Germany Priority TIMER FOR CONTROLLING THEOPERATION OF DEVICES AND IMPLEMENTS, ESPECIALLY STOVES [5 6] ReferencesCited UNITED STATES PATENTS 3,098,131 7/1963 Gallagher et al 200/38Primary Examiner-Richard B. Wilkinson Assistant Examiner-Edith C.Simmons Attorney-Walter Becker ABSTRACT: A timing mechanism especiallyfor cooking appliances, in which a pointer is adjustable over a clockface to indicate the end of a cooking period, while a dial is adjustableto indicate the duration of the cooking period. A planetary geararrangement interconnects the dial and the pointer and adjusts one of apair of clutch elements, the other of which is driven by the timermotor. Adjustment of the dial presets a power control device and whenthe clutch parts are in a certain relative position they clutch togetherand initiate the supply of power to the appliance, and which isautomatically terminated when the preselected time expires.

PATENTEU 0m 5 l9?! sum 1 OF 3 IN VEN TOR. J05EF NEUBAUER.

PATENTEDnm 51971 3610.753

sum 2 or 3 INVENTOR. 30551 NEUBA UER.

PATENTED um 512m p 6 1 O 7 5 3 SHEET 3 UF 3 SET POINTER 5 7 POINTER 5 "1FIRST SET DIAL u 521% ELEMENT I 8560K 4| SECOND TIMER ELEMEN 5, z MOTOR"LINK L BELLCRANK ACTUATING CONTROL SPRING s SWITCH INVENTOR JOSEFNEUBAUER TIMER FOR CONTROLLING THE OPERATION OF DEVICES AND IMPLEMENTS,ESPECIALLY STOVES The present invention relates to a timer forcontrolling the operation of devices and implements, especially stoves.In particular the operation concerns a device for kitchen stoves withmeans for setting the end of a cooking period, the duration of a cookingperiod, a particularly short cooking period, and the start of thecooking period while indicating means are provided for the threelast-mentioned setting means. The device is furthermore provided with aplanetary gear transmission for calculating and setting the time for thestart of the cooking period from the present termination of the cookingperiod and the duration of the cooking period. The device also comprisesa drive for the timer which simultaneously furnishes the energy for themechanical control operations and furthermore comprises electric controlmeans for controlling the functions of the device.

A timer of this type for use in kitchen stoves is known. Such knowntimers comprise a total of three actuating shafts for setting the timeof day for the timer, for setting the cooking 7 duration, and forsetting a particularly short cooking period while the actuating shaftfor the timer is additionally equipped with a hollow shaft for settingthe end of the cooking period. For visually indicating the set timeconcerning the end of the cooking period, the duration of the cookingperiod and the particularly short cooking period there are provided atotal of three indicating devices. The most important feature of such atimer is its planetary gear transmission by means of which after havingset the end of the cooking period and the cooking duration, the start ofthe cooking period is automatically set in the timer so that the personoperating the stove does under no circumstances have to make timeconsuming calculations in this respect. The timer, however, requires aconsiderable space in view of the fact that three actuating shafts arearranged adjacent to each other including the pertaining indicatingdevices.

It is, therefore, an object of the present invention to improve a timerof the above-mentioned type so that a timer will be realized which has aconsiderably decreased height and width while the functions andindicating possibilities of the heretofore known timers will be retainedto their full extent.

This object and other objects and advantages of the invention willappear more clearly from the following specification in connection withthe accompanying drawings, in which:

FIG. I is a front view of a timer according to the invention.

FIG. 2 is a diagrammatic illustration for purposes of explaining thefunction of the timer according to the invention.

FIG. 3 is a lateral section through the timer according to the inventionwhile the transmission for setting the time for a particularly shortcooking period has been omitted.

FIG. 4 is a lateral section similar to that of FIG. 3 while only thetransmission for the setting of a particularly short cooking period isillustrated.

FIG. 5 is a top view of the transmission of FIG. 4.

FIG. 6 is a perspective view of the structures shown in FIGS. l5.

The present invention is characterized primarily in that a timer ismounted on the front plate of the stove while a first actuating shaftfor setting the end of the cooking period is provided which carries ahollow shaft for setting a particularly short cooking period. Theinvention is furthermore characterized in that a second actuating shaftfor setting the beginning of the cooking period is provided and carriesa hollow shaft for setting the cooking period. The invention isfurthermore characterized in that the first actuating shaft with theindicating device for the cooking period and the hollow shaft mounted onsaid first actuating shaft and provided with an indicating device forthe particularly short cooking period and the hollow shaft on the secondactuating shaft are mechanically connected or coupled to the indicatingdevice for the cooking time.

Thus, according to the present invention, the number of the actuatingshafts is reduced. This in turn permits a considerable decrease in theoverall size of heretofore known timers inasmuch as in view of the newarrangement of the actuating shafts simultaneously also the geartransmission arranged behind the front plate can be compacted to aconsiderable extent.

A further-decrease in the overall size of the timer has been madepossible according to the invention by the fact that the indicatingdevice for the end of the cooking period consists of an indicator whichby means of a hollow shaft is arranged on the shaft of the timer.Consequently, no indicating device for the end of the cooking period isnecessary which would require a space of its own. The indicating devicesfor the cooking period and for the particularly short cooking periodrespectively consist of an indicating disc with corresponding numberswhich are partly visible behind a window of the front plate. Theseindicating devices are similar to the indicator for the end of thecooking period coupled through gears with the actuating shafts and thehollow shafts arranged thereon.

According to a further development of the device according to theinvention, the indicating discs for the cooking period are also coupledto the drive for the timer in such a way that the discs rotate with theexpiration of the set time in a direction counter to the settingdirection so that always the time still left is indicated.

According to a still further development of the present invention, thefirst actuating shaft (end of the cooking period) is through drivingmeans operatively connected to the sun wheel of the planetary geartransmission while the hollow shaft on the second actuating shaft(cooking time) is coupled to the outer wheel of said planetary geartransmission. Furthermore, the planetary gear wheel is operativelyconnected to coupling means which at the start of the cooking periodactuate an electric switch for the supply of current, and connect theplanetary gear transmission to the drive for the timer. The outer wheelof the planetary gear transmission cooperates with a control lever whichat the end of the cooking period-a certain position of the outer wheelbeing associated with the control lever-actuates an electric breaker forthe current supply and furthermore through the intervention of thecoupling means separates the planetary gear transmission from the drivefor the timer.

The coupling means according to a further development of the inventioncomprises an axially displaceable coupling disc provided with a bore orgroove and also comprises a clutch jaw connected to the planetary gearwhich jaw cooperates with the bore or groove of the coupling disc in apositive manner when the clutch is engaged.

Furthermore, according to the invention, there may be provided a brakebetween the sun wheel of the planetary gear transmission and the firstactuating shaft which brake has such a braking moment that on one handthe driving energy of the drive for the timer will not be sufi'rcient toturn the sun wheel while on the other hand a setting of the end of thecooking period through the first actuating shaft will be possiblewithout difficulties.

Referring now to the drawings in detail, FIG. 1 illustrates the dialface of the timer I mounted on a front plate F. The timer furthermorecomprises a pointer 2 for indicating the hours and a pointer 3 forindicating the minutes while the seconds are indicated by the pointer 4.For purposes of setting the end of the cooking period, there is provideda setting indicator 5. The actuation of the functions of the timer iseffected by a total of four control knobs arranged on two double shafts.By means of the knob 6 the end of the cooking period is set while at thesame time the adjusting indicator 5 is moved. By means of a knob 7 atimer for a particularly short cooking period is set which at theexpiration of said short time sounds off. The setting of the pointers 2and 3 is effected by a knob 8. A fourth knob 9 serves for setting theintended cooking duration. For purposes of indicating the particularlyshort cooking period and the longer cooking periods, there arerespectively provided two indicating devices 10 and 11 with dialsvisible through a window 10' and 11; of the front plate F. Thearrangement of the indicating dials is such that the respective stillremaining time of the set time is indicated.

The operations of the timer according to the invention will now beexplained in connection with the diagrammatic illustration of FIG. 2. Acoupling disc 20 rotates synchronously with the hour wheel 2 of thetimer, said coupling disc being provided with a cutout 21.Simultaneously with the turning of the pointer 5 for the end of thecooking period, a clutch jaw 22 is by means of a differential turned tothe same extent. Through the intervention of the outer wheel 23 of aplanetary gear transmission, the cooking period is set while the outerwheel is turned in the direction of the arrow 24. A cam switch 25cooperating with a groove 26 provided at the circumference of the outerwheel 23 serves for controlling the electric functions of the kitchenstove. The numbering provided on the outer wheel 23 is in this figureshown merely for facilitating the understanding.

There will now be explained the operation of the timer for a freelyselected example. It may be assumed that at the time of day shown inFIG. 1, namely 4:48 PM, the timer is started and the end of the cookingperiod is to be set for 7 PM while the cooking period proper should beone hour. By means of the setting knob 6 the indicating pointer 5 andtogether with the latter the clutch jaw 22 is set for the time 7 PM(position 22 in FIG. 2). Thereupon the outer wheel 23 is by means of theknob 9 turned in the direction of the arrow 24 by one hour which meansthat the number one on the outer wheel 23 occupies the position wherepreviously the number 12 had been. In view of this turning movement,through the intervention of the set differential, the coupling jaw 22 isturned back from its position 22' by a corresponding angle to theposition 22" and now indicates the start of the cooking period. Byturning the outer wheel 23, the release lever 25 was also lifted out ofthe groove 26.

With progressing time, the clutch disc with the recess 21 moves inclockwise direction and eventually reaches the time 6 PM. At this time,the clutch jaw 22 which occupies the position 22" drops into the recess21 and is by means of the clutch disc 20 positively taken along. Due tothe dropping of the clutch jaw 22 into the cutout 21, simultaneously thecurrent supply to the kitchen stove is turned on. In view of the factthat the clutch jaw 22 is moved, simultaneously through the interventionof the set differential also the outer wheel 23 is turned counter to thedirection of the arrow 24 until the time of 7 PM has been reached. Atthis time, the release lever 25 drops back into the groove 26 and thusturns off the current supply to the stove. Furthermore the clutch jaw 22is again lifted out of the cutout 21.

The mechanical construction of the timer will be evident from FIG. 3.The shafts on which the knobs 6-9 referred to in connection with FIG. 1are arranged are designated with the reference numerals 6'9. Theremaining structural elements referred to and discussed in FIGS. 1 and 2are in FIG. 3 designated with the same reference numerals as in FIGS. 1and 2. The gear train for setting a particularly short cooking time bymeans of shaft 7' with the gear 30 has been omitted in FIG. 3 to avoidclogging up the latter and is illustrated separately in FIGS. 4 and 5.

Shaft 6' has mounted thereon a gear 31 which meshes with the gear 32.The pointer 5 for indicating the end of the cooking period is connectedto the shaft 33 of gear 32 which shaft 33 forms a hollow shaft and isarranged on the shaft of the pointers 2, 3 and 4. A braking disc 35provided with a brake liner is pressed against the gear 32 by means oftwo springs 34 resting against the front plate F. This braking discexerts upon the gear 32 and thereby the pointer 5 such a braking momentthat while it is possible to turn the pointer 5 manually through shaft6', a turning of the pointer 5 by the drive of the timer will not bepossible.

A gear 36 which is connected to the main shaft 37 of the planetary geartransmission meshes with the gear 32. This planetary gear transmissioncomprises the above-mentioned outer wheel 23 which is freely journaledon shaft 37 and has inner and outer teeth. The planetary geartransmission furthermore comprises a sun wheel 38 connected to shaft 37,and also a planetary gear wheel 39 arranged between the sun wheel 38 andthe inner teeth of the outer wheel 23. Planetary gear wheel 39 isrotatably mounted on a disc 40 which latter is freely rotatable on shaft37. Disc 40 has fixedly connected thereto the above mentioned clutch jaw22.

Axially displaceably mounted on shaft 37 is the above mentioned clutchdisc 20 with the cutout 21. This clutch disc 20 is driven through agear41 which is operatively connected to the drive for the timer. Bymeans of a lever 42, the clutch disc 20 is by a force 42' pressedagainst the clutch jaw 22 against the thrust ofa spring 43.

The setting of the pointers 2 and 3 is effected through shaft 8 and agear 44. Shaft 9' has mounted thereon a gear 45 which on one hand mesheswith the indicating disc 11 visible through a window 11' in the frontplate F and intended for the cooking period and on the other hand withthe outer teeth of the outer gear 23 of the planetary gear transmission.

In view of the general explanation of the operation of the timer inconnection with FIG. 2, the mode of function of the arrangement of FIG.3 will be evident. By turning the shaft 6', the pointer 5 for the end ofthe cooking time will be set through the intervention of the gear 3! andthe gear 32. Simultaneously, the sun wheel 38 is rotated through thegear 36, and the rotation of the sun wheel 38 brings about that theplanetary gear 39 rolls on the inner teeth of the outer wheel 23 of theplanetary gear transmission. In this way, however, the disc 40 on whichthe planetary gear is journaled and thus also the clutch jaw 22 will berotated to a corresponding extent. In conformity with theabove-mentioned example of operation, it is assumed that the clutch jawcannot drop into the cutout 21 of the clutch wheel 20. By turning theshaft 9' the setting for the cooking period is now effected. In view ofthis turning movement, not only the indicating disc 11 is turned throughthe intervention of the gear 45 but at the same time also the outerwheel 23 of the planetary gear transmission is turned through theintervention of the outer teeth. Furthermore, the release lever 25 notvisible in FIG. 3 is lifted out of the groove 26 (FIG. 2) and the clutchis prepared for the later coupling operation. In view of the turning ofthe outer wheel 23, due to the inner teeth of wheel 23, simultaneouslyalso the planetary gear wheel 39 is rotated and rolls on the innerteeth. In order to assure that the setting movement of shaft 9 actsthrough the outer wheel 23 fully upon the planetary wheel 39, it isnecessary that the sun wheel 38 is braked fast. This is effected bymeans of the braking disc 35 and the gears 32 and 36. By means of theouter wheel 23, the planetary gear wheel is rotated in a directionopposite to the direction of rotation when the end of the cooking periodis set. Consequently, disc 40 with the clutch jaw 22 is turned back by astep in conformity with the set cooking period.

The drive for the timer drives also the gear 41 as mentioned above sothat the clutch wheel 20 will rotate synchronously with the expiringtime. As soon as the clutch jaw 22 faces the cutout 21, the clutch wheel20 due to the pressure exerted by the relief lever 42 is displacedagainst the thrust of the spring 43 and will when turned furtherpositively engage and move the clutch jaw 22 and disc 40. The planetarygear wheel will in view of the movement of the disc 40 continue to rollon the inner teeth of the outer wheel 23 while the sun wheel 38 remainsbraked fast and now turns back the indicating disc 11 through theintervention of the outer wheel 23 and the gear 45. When eventually thecooking time has ended, the relief lever 25 drops into the groove 26 onthe outer wheel 23 (FIG. 2) and simultaneously brings about a returnpivoting of the lever 42 and makes the force ineffective in thedirection of the arrow 42'. The clutch wheel will thereby in view of thespring pressure 43 be displaced axially and will again occupy its endposition while not being engaged by the clutch jaw 22.

The setting of a short cooking period will be evident from FIGS. 4 and5. The indicating disc 10 which is provided with numbers and which isvisible from the outside through a window in the front plate F mesheswith the gear 30 connected to the hollow shaft 7'. Connected to theshaft 50 of disc 10 is a gear 51 and a cam disc 52. The gear 51 mesheswith a gear 53 which is freely rotatable on a shaft 54. This gear 53through a clutch liner 55 cooperates with a disc 56 connected to shaft54. For purposes of producing the necessary pressure, there is provideda spring 57 which is coaxially arranged with shaft 54 and rests againsta disc 58 connected to the shaft 54. A nose 61' of a lever 61 pivotableabout a shaft 60 cooperates with a groove 59 in the cam disc 52. Lever61 is under the influence of a force acting in the direction indicatedby the arrow 62. The free end of lever 61 is provided with a member 63which is adapted to hit against a bell 64.

The gear 51 is within the range between the teeth 51 and 51" free fromteeth to disengage the timer for setting a short cooking period from theshaft 54 which is driven by the drive for the timer when no shortcooking period has been set. The clutch on the shaft 54 serves formaking possible the setting of a very short cooking period via shaft 7'without simultaneously damaging the drive running in the oppositedirection.

The setting of a very short cooking period is effected in such a waythat the shaft 7" and therefore through gear 30 also the indicating disc10 is turned in a corresponding manner. Simultaneously the gear 51 andthe cam disc 52 are turned. Due to this turning movement, the lever 61with its nose 61 is lifted out of the groove 59 of the cam disc 52 andsimultaneously the teeth of gear 51 are brought into meshing engagementwith the gear 53. if now the shaft 7 is relieved, the drive for thetimer will through the intervention of gear 53 bring about that the gear51 and the cam disc 52 as well as the indicating disc 10 turn in adirection opposite to the setting direction. As soon as the gear 53leaves the effective range of the teeth at 51', the nose of lever 61drops into groove 59 and simultaneously the member 63 hits against thebell 64.-

While the present invention has been described in connection with atimer for setting a short cooking period operating in such a way thatthe member 63 hits against the bell 64, it is, of course, obvious thatthe movement of the lever 61 may also actuate another indicating deviceas, for instance, an electric switch which in its turn makes effective abell or a buzzer for a desired period of time. Parts relationship of thestructures identified by the foregoing reference numerals can be seenmore readily in FIG. 6.

It is, of course, also to be understood that the present invention is byno means limited to the particular showing in the drawings but alsocomprises any modifications within the scope of the appended claims.

What is claimed is:

l. A timer mechanism, especially for use with appliances such as cookingstoves, comprising: a frame with a clock, first manual means foradjusting the end of a time period with a pointer, second manual meansin coaxial relation to the first manual means for adjusting a short-timeperiod, third manual means for adjusting the time, fourth manual meansin coaxial relation to that third manual means for adjusting a selectedtime period which is to end at the time indicated by the pointer, thesecond manual means being mechanically con nected with a first dial forindicating the short time period and the fourth manual means beingmechanically connected witha second dial indicating the said timeperiod, the said clock having a face and hands, a tubular shafttelescoping the shafts for said hands, the said pointer being mounted onsaid tubular shaft and indicating the end ofthe selected time period onsaid clock face, a clutch having a first disc driven by the driven shaftmeans of the clock and also having a second disc coaxial with said firstdisc, a spring urging said discs apart and clutch actuating meansoperable for resiliently urging said discs toward each other, clutchelements on said discs engageable only when in registration and saidclutch discs are urged toward each other by said clutch actuating means,a control arm biased toward a first position and having a secondposition and said positions corresponding respectively to appliancepower-off and appliance power-on, a rotatable cam engaging said arm andpermitting said arm to move to said first position thereof in only onerotated position of said cam, means making said clutch actuating meansineffective in said one position of said arm, and a three elementplanetary gear drive having a first element connected to said seconddisc and a second element connected to said pointer and to said firstmanual means and a third element connected to said cam and to saidsecond dial and to said fourth manual means.

2. A timer mechanism according to claim 1 which includes a clock in saidframe having a face and hands, and a tubular shaft telescoping theshafts for said hands, said pointer being mounted on said tubular shaftand indicating the end of the selected time period on said clock face.

3. A timer mechanism according to claim 2, in which said frame has afront portion, said clock face and first dial being observable fromfront of said frame, said first and fourth manual means comprising firstand second knobs respectively at the front portion of said frame.

4. A timer mechanism according to claim 3, a said second manual meansbeing in the form of a second knob connected to said first dial forrotation thereof, timer further includes friction drive means forconnecting said first dial with said timer driven shaft means, saidfirst dial being disengaged from said friction drive means in oneadjusted position only of the first dial, and signal means actuated bysaid first dial in response to movement thereof into said one position.

5, A timer mechanism according to claim 4, wherein said third manualmeans includes a third knob for adjusting said clock hands, said firstand second knobs being arranged in coaxially relation at said frontpanel, and said second and third knobs being arranged in coaxialrelation at said front panel in spaced relation to said first and thirdknobs.

6. A timer mechanism according to claim 5, in which said frame has afront panel with a window formed therein for said clock face and withapertures therein through which marginal regions of said first andsecond dials are visible.

7. A timer mechanism according to claim 6, in which said first andsecond dials have gear teeth, and gears meshing with said gear teeth andconnected to the respective knobs.

8. A timer mechanism according to claim 6, in which the first and seconddials are moveable by the respective knobs therefor away from a zeroposition into position to indicate respective time periods and are movedin the direction of decreasing time display by said timer driven shaftmeans.

9. A timer mechanism according to claim 8, in which the said first andsecond dials and the respective viewing apertures therefor are adjacentthe respective knobs.

10. A timer mechanism according to claim 4, in which coaxial ones ofsaid knobs are mounted on telescoping rotary shafts.

11. A timer mechanism according to claim 6, in which said first elementof said planetary gear drive is the planet gear and a shaft mounted onsaid second disc rotatably supports said planet gear, said secondelement comprising the sun gear and means connecting the sun gear tosaid pointer and said first manual means, said third element comprisingthe ring gear, and means connecting said ring gear to said cam and tosaid first dial and to said second manual means.

12. A timer mechanism according to claim 11, in which said cam iscoaxial with and mounted on said ring gear.

13. A timer mechanism according to claim 11, in which said clutchelements comprise a hole in one of said discs and a projection on theother of said discs receivable in said hole.

14. A timer mechanism according to claim 12, in which said cam iscircular with a single peripheral notch therein, said control arm havinga follower bearing on the periphery of said cam and receivable in saidnotch.

15. A timer mechanism according to claim 14, in which the resistanceoffered to rotation of said pointer and sun gear by said friction meansis adequate to prevent rotation of said sun gear when said planetarygear is driven about the sun gear by rotation of said second disc andalso when said ring gear is rotated by said second manual means.

1. A timer mechanism, especially for use with appliances such as cookingstoves, comprising: a frame with a clock, first manual means foradjusting the end of a time period with a pointer, second manual meansin coaxial relation to the first manual means for adjusting a short-timeperiod, third manual means for adjusting the time, fourth manual meansin coaxial relation to that third manual means for adjusting a selectedtime period which is to end at the time indicated by the pointer, thesecond manual means being mechanically connected with a first dial forindicating the short time period and the fourth manual means beingmechanically connected with a second dial indicating the said timeperiod, the said clock having a face and hands, a tubular shafttelescoping the shafts for said hands, the said pointer being mounted onsaid tubular shaft and indicating the end of the selected time period onsaid clock face, a clutch having a first disc driven by the driven shaftmeans of the clock and also having a second disc coaxial with said firstdisc, a spring urging said discs apart and clutch actuating meansoperable for resiliently urging said discs toward each other, clutchelements on said discs engageable only when in registration and saidclutch discs are urged toward each other by said clutch actuating means,a control arm biased toward a first position and having a secondposition and said positions corresponding respectively to appliancepower-off and appliance power-on, a rotatable cam engaging said arm andpermitting said arm to move to said first position thereof in only onerotated position of said cam, means making said clutch actuating meansineffective in said one position of said arm, and a three elementplanetary gear drive having a first element connected to said seconddisc and a second element connected to said pointer and to said firstmanual means and a third element connected to said cam and to saidsecond dial and to said fourth manual means.
 2. A timer mechanismaccording to claim 1 which includes a clock in said frame having a faceand hands, and a tubular shaft telescoping the shafts for said hands,said pointer being mounted on said tubular shaft and indicating the endof the selected time period on said clock face.
 3. A timer mechanismaccording to claim 2, in which said frame has a front portion, saidclock face and first dial being observable from front of said frame,said first and fourth manual means comprising first and second knobsrespectively at the front portion of said frame.
 4. A timer mechanismaccording to claim 3, a said second manual means being in the form of asecond knob connected to said first dial for rotation thereof, Timerfurther includes friction drive means for connecting said first dialwith said timer driven shaft means, said first dial being disengagedfrom said friction drive means in one adjusted position only of thefirst dial, and signal means actuated by said first dial in response tomovement thereof into said one position.
 5. A timer mechanism accordingto claim 4, wherein said third manual means includes a third knob foradjusting said clock hands, said first and second knobs being arrangedin coaxially relation at said front panel, and said second and thirdknobs being arranged in coaxial relation at said front panel in spacedrelation to said first and third knobs.
 6. A timer mechanism accordingto claim 5, in which said frame has a front panel with a window formedtherein for said clock face and with apertures therein through whichmarginal regions of said first and second dials are visible.
 7. A timermechanism according to claim 6, in which said first and second dialshave gear teeth, and gears meshing with said gear teeth and connected tothe respective knobs.
 8. A timer mechanism according to claim 6, inwhich the first and second dials are moveable by the respective knobstherefor away from a zero position into position to indicate respectivetime periods and are moved in the direction of decreasing time displayby said timer driven shaft means.
 9. A timer mechanism according toclaim 8, in which the said first and second dials and the respectiveviewing apertures therefor are adjacent the respective knobs.
 10. Atimer mechanism according to claim 4, in which coaxial ones of saidknobs are mounted on telescoping rotary shafts.
 11. A timer mechanismaccording to claim 6, in which said first element of said planetary geardrive is the planet gear and a shaft mounted on said second discrotatably supports said planet gear, said second element comprising thesun gear and means connecting the sun gear to said pointer and saidfirst manual means, said third element comprising the ring gear, andmeans connecting said ring gear to said cam and to said first dial andto said second manual means.
 12. A timer mechanism according to claim11, in which said cam is coaxial with and mounted on said ring gear. 13.A timer mechanism according to claim 11, in which said clutch elementscomprise a hole in one of said discs and a projection on the other ofsaid discs receivable in said hole.
 14. A timer mechanism according toclaim 12, in which said cam is circular with a single peripheral notchtherein, said control arm having a follower bearing on the periphery ofsaid cam and receivable in said notch.
 15. A timer mechanism accordingto claim 14, in which the resistance offered to rotation of said pointerand sun gear by said friction means is adequate to prevent rotation ofsaid sun gear when said planetary gear is driven about the sun gear byrotation of said second disc and also when said ring gear is rotated bysaid second manual means.